1. Field of the Invention
The present invention relates to an interchangeable lens camera with a lens barrel detachably disposed in a camera body, and in particular, it relates to a mounting device for a lens barrel in an interchangeable lens camera which can detachably mount, and in addition cause to collapse, the interchangeable lens barrel in the camera body.
2. Description of the Related Art
In interchangeable lens cameras, generally, the lens barrel is mounted to be freely detachable with respect to the camera body. A screw-in type lens barrel attached by a screw mount is known as is a detachably spring-mounted type lens barrel attached by a bayonet mount.
Namely, in the screw-in type lens barrel, the structure was such that screw portions were disposed on the lens receiving aperture portion of the camera body and the rear end side of the lens barrel. The lens barrel (interchangeable lens) was caused to rotate by causing both screw portions to engage and be joined, and thus, it was freely detachable with respect to the camera body.
In the spring-mounted type lens barrel, the structure was such that the lens barrel, by causing rotary movement in a predetermined angular direction with respect to the camera body, was also freely detachably mounted.
In interchangeable lens cameras with such an interchangeable type lens barrel that is freely detachably mounted in the camera body, a small size, light weight design is also known in which the lens barrel collapses within the camera body. For example, such a camera is disclosed in Japanese Laid-Open Patent Publication JPA-56-91224.
In this interchangeable lens camera, the lens barrel is freely detachably disposed in a mounting unit on the front surface side of the camera body. Also, this lens barrel is formed so as to move back and forth along the optical axis direction with respect to this mounting unit. In this camera, in order to make the lens barrel capable of extension within the camera body, a lens type shutter is adopted. In addition, in the forward direction of the film surface within the camera body, when movement of the lens barrel lead to removal thereof, for example opening and closing by coupling the lens barrel during rotation of a bayonet coupling, a screening plate device is disposed to screen off the light path towards the film surface.
Then, the construction was to cause collapsing, causing this screening plate device to pass through, leaving this screening plate device open, coupling by rotary movement during mounting of the lens barrel to the camera body, and also to cause the lens barrel to move extending on the film surface side along the optical axis direction.
However, in the above interchangeable lens cameras, the mounting member of the lens barrel had to be formed in the outer circumferential portion of the lens barrel which was the front surface portion of the camera body. In particular, not only did it become a hindrance to obtain a good external appearance, but the drive mechanism of the lens barrel became unnecessarily large due to the fact that the mounting member was larger than the diameter of the lens barrel. As a result, this construction has become an obstacle to miniaturization.
Because of this, it was desirable to adopt measures for improving the mounting unit structure for the camera body side, making the lens barrel freely detachably interchangeable, thus bringing about an improvement in the external appearance of the camera, and in addition, allowing the camera to be designed with a smaller size.
For example, in a known detachable lens camera, it is known for the mounting unit of the lens barrel to be movable back and forth in the optical axis direction within the camera body. However, such a camera causes a photographic lens focusing action by movement in the optical axis direction while rotating the mounting unit itself, thus requiring a special mechanism in order to cause the lens barrel to move in the optical axis direction. This requirement complicates the structure.
Moreover, in such a structure, the external appearance was excellent when the mounting unit of the lens barrel was assembled in the camera body. However, because the mounting unit itself rotated when moving in the optical axis direction, there was a problem that the transmission of motive power or the transmission of electrical signals between the camera body and the lens barrel was difficult. The problem had to be taken into account for improving the mounting unit structure.
Accordingly, it is an object of the present invention to overcome the above problems of the above known cameras.
It is also an object of the present invention to obtain an interchangeable lens camera which is designed for a small-sized camera body, and which can simply and accurately mount a lens barrel to a camera body.
Furthermore, another object of the present invention is to provide an interchangeable lens camera having a lens barrel that can collapse within the camera body by a movement along the optical axis direction, without limitation to the external appearance of the camera.
Objects of the present invention are achieved by an interchangeable lens camera comprising a mounting device for interchangeably mounting a lens barrel on a camera body, the mounting device being disposed to prevent rotation about an optical axis and to move back and forth in an optical axis direction, and the mounting device, by moving in the optical axis direction, receiving the lens barrel in the camera body.
Still further objects of the present invention are achieved by an interchangeable lens camera comprising a camera body, a lens barrel with focusing lenses, a first mounting device disposed in the lens barrel, and a second mounting device disposed in the camera body, wherein the first and second mounting devices act to mount the lens barrel to the camera body and to electrically and mechanically connect the lens barrel and the camera body, and wherein the lens barrel is movable along an optical axis of the focusing lenses so as to be movable from a first fully collapsed position where the lens barrel is fully collapsed within the camera body to a second fully extended telephoto position.
Objects of the present invention are also achieved by an interchangeable lens camera wherein a lens barrel mounting device is prevented from rotating around the optical axis within the camera body, and is movable in the optical axis direction. When the lens barrel is in a state in which it has moved as far as an extended position in the camera body, in this state a retracting movement of the mounting device is caused by movement back and forth in the camera body. An electrical drive member of a lens barrel side and a control circuit of the camera body side are electrically connected by causing the mounting device to move as far as the collapsed position.
Moreover, objects of the present invention are also achieved by an interchangeable lens camera which allows the lens barrel mounting device to move linearly as far as an extended position along the optical axis direction within the camera body. Also, the shortest length of the camera is when the lens barrel is detached from the camera body.
Furthermore, at the time of removal of the lens barrel from the camera body, a lens protection member, which opens and closes a photographic optical path at the front surface side of the lens barrel, is closed.
The lens barrel mounting device is for example constituted by a body side mount and a lens side mount. Moreover, the back and forth movement, for example, is accomplished by a set tube. Furthermore, the electrical mechanism units on the camera body side are, for example, a control circuit or units connected to the control circuit, motors used for focus drive, and a zooming motor. As mechanical mechanism units, there are, for example, coupling gears for use in zoom driving.
Moreover, a shutter and a focusing drive unit, which are connected via an electrical transmission device by connection pins and the like formed of electrically conductive materials, serve as the electrical drive members within the lens barrel. Furthermore, the lens protection member, for example, is formed of a light shielding plate disposed in an aperture portion of the camera body.